Replaceable demolition shear piercing tip

ABSTRACT

A heavy-duty demolition shear with a replaceable shearing tip has a lower jaw and an upper jaw piviotally connected to the lower jaw. The upper jaw has primary and secondary shear blades. A replaceable shearing tip is mounted to the upper jaw. The replaceable shearing tip has two L-shaped sections which engage the upper jaw between them. The replaceable shearing tip engages the upper jaw on at least three seats. The replaceable shearing tip is connected to the upper jaw by socket-head cap-screws.

BACKGROUND OF THE INVENTION

A fuller understanding of the operation of the demolition apparatus ofthe present invention may be achieved by studying U.S. Pat. No.4,519,135, hereby incorporated by reference. This invention relates to aheavy duty demolition apparatus, especially adapted to be mounted on arigid boom of a mobile vehicle and particularly adapted to be mounted onthe dipper stick of an excavator.

The invention also has a replaceable shearing tip on the movable upperjaw.

Heavy duty shears of the type that are powered by hydraulic cylindersare proving more and more useful in handling scrap and especially metalscrap of all sorts. Such scrap comes in many different forms, and may bein the form of pipes made of steel or soft iron or cast iron, ranging insizes from 2 inches or smaller, and up to 8 or 10 inches in diameter orlarger; structural beams such as I-beams, channels, angle beams in alarge range of sizes, up to 8 or 10 inches across and larger; rods andheavy cables having diameters of 2 to 3 inches and larger, metal sheetsand plates and formed metal of all sorts including wheels and automobileand truck frames, and a myriad of long and short pieces of stock andmetal pieces that are cast, rolled, stamped or otherwise formed, bothsingly and in various types of assembly.

The prior art has included numerous shears such as that illustrated inU.S. Pat. No. 4,198,747; U.S. Pat. No. 4,188,721; U.S. Pat. No.4,897,921; U.S. Pat. No. 4,543,719; U.S. Pat. No. 4,558,515 and U.S.Pat. No. 4,104,792. Typically, these heavy duty shears mount on thedipper stick of an excavator so that the shears may be controlled fairlywell in handling various types of scrap and cutting the scrap intosmaller twisted and contorted pieces and lengths as the scrap is drawninto the throat of the shear.

Typically, these shears have a fixed lower jaw and a movable upper jawthat pivots on the lower jaw, with shear blades of hardened steel onboth the upper jaw and the lower jaw. The workpiece is sheared byclosing the upper jaw against the lower jaw under hydraulic pressure,with the shear blades cutting the workpiece. The movable upper jaw mayalso have a fixed, hardened shearing tip integral with the upper jaw.The tip is not suitable for removal and replacement due to the highlateral forces exerted on the tip as the movable jaw flexes laterally.Great tension is also exerted upon the tip, which may be wedged tightwith scrap, upon opening the jaws. Direct shear bearing loads are alsoon the tip when shearing. All these factors will cause a removable tipto readily break off the upper jaw.

There is a need for a heavy duty demolition shear with a replaceableshearing tip

SUMMARY OF THE INVENTION

A heavy-duty demolition shear with a replaceable shearing tip has alower jaw and an upper jaw piviotally connected to the lower jaw. Theupper jaw has primary and secondary shear blades. A replaceable shearingtip is mounted to the upper jaw. The replaceable shearing tip has twoL-shaped sections which engage the upper jaw between them. Thereplaceable shearing tip engages the upper jaw on at least three seats.The replaceable shearing tip is connected to the upper jaw bysocket-head cap-screws.

A principal object and advantage is that the upper jaw has a replaceableshearing tip.

Another object and advantage is that the replaceable tip is held inplace by socket-headed cap-screws which will hold the tip in placedespite high direct and lateral/forces, as well as stress shearingforces and tensional forces exerted on the tip when opening the shearwith jammed scrap pieces about the tip.

Another object and advantage is that the tip is supported on the upperjaw on at least three seating surfaces, which alleviates stress shearingforces and tensional forces.

Another object and advantage of the present invention is that the tipencapsulates the upper jaw and prevents the upper jaw from being damagedby forces exerted on the tip.

Other advantages will be understood from reading the DetailedDescription of Preferred Embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a right-side perspective view of the demolition apparatus withthe replaceable shearing tip of the present invention, showing the tipassembled on the apparatus.

FIG. 2 is like FIG. 1, but with the tip exploded off the apparatus(disassembled).

FIG. 3 is similar to FIG. 2, but is a left-side perspective view.

FIG. 4 is similar to FIG. 1, but is a left-side perspective view.

FIG. 5 is a partial right-side elevational view of the upper jaw of theapparatus with the tip mounted thereon, showing various angles.

FIG. 6 is a cross-section at approximately the lines 6 of FIG. 5.

FIG. 7 is similar to FIG. 5, showing additional angles.

FIG. 8 is similar to FIG. 6, showing additional dimensions.

FIG. 9 is similar to FIG. 5, showing additional angles.

FIG. 10 is similar to FIG. 5, showing additional angles.

FIG. 11 is similar to FIG. 5, showing additional angles.

FIG. 12 is similar to FIG. 5, showing additional angles.

FIG. 13 is a right-side elevational view of the apparatus of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The heavy-duty demolition apparatus of the present invention isgenerally referred to in the Figures as reference numeral 10.

Referring to FIGS. 1 through 6, the heavy-duty demolition apparatus 10comprises a lower jaw 12, an upper jaw 14, and pivot means 16interconnecting the lower jaw 12 and upperjaw 14.

The upper jaw 14 has a first side 22, and a second side 24. The lowerjaw 12 has a first mounting plate 26 adjacent the first side 22, and asecond mounting plate 28 adjacent the second side 24. The first mountingplate 26 and second mounting plate 28 receive the pivot means 16 betweenthem.

The upper jaw 14 has upper shear blades 33 and 34 meeting at apex 35 andthe lower jaw 12 has lower shear blades 36 and 37 extending along eachother for shearing a workpiece when the upper shear blades 33 and 34 areclosed upon the lower shear blades 36 and 37. Preferably, the shearblades 33, 34, 36 and 37 are replaceable.

Preferably, the apparatus 10 further comprises a guide blade 48 on thelower jaw 12 lying along the lower shear blade 36 and in spaced relationtherewith, the outer end 50 of the guide blade and outer end 52 of theshear blade being adjacent each other, and rigid means 54 securing theouter ends 50, 52 together. The rigid means 54 is preferably a tie plate56.

An open slot 58 preferably exists between the lower shear blade 36 andthe adjacent guide blade 48 to receive the upper shear blade 34 therein,the open slot 58 having a width wider than the thickness of the uppershear blade 34 to maintain open space between the upper shear blade 34and the guide blade 48 when the upper shear blade 34 is in the open slot58.

On the first shearing side 22, the upper jaw will receive the upperprimary shear blade 31 and the upper secondary shear blade 33. The shearblades 31 and 33 meet at the upper shear blade apex 35 which is the lastpoint wherein the upper jaw 14 shears a workpiece against lower elongateshear blade 36. On the lower jaw 12, the lower primary shear blade 36and lower secondary shear blade 37 are received.

To accommodate secure attachment of the replaceable shearing tip 110,the upper, movable jaw 14 is modified to include a tip mounting portion60, as seen in FIGS. 1-4.

The tip mounting portion 60 further comprises a first mounting surface60 a on the first side 22 of the upper jaw 14, and a second mountingsurface 60 b on the second side 24. A third mounting surface 60 c islocated on the bottom side of the upper jaw 14 between the firstmounting surface 60 a and the second mounting surface 60 b. A fourthmounting surface 60 d is located above each of the first 60 a and second60 b mounting surfaces on the upper jaw 14. Between the first mountingsurface 60 a and the second mounting surface 60 b is narrowed upper jawtip portion 70.

The replaceable shearing tip 110 comprises a first half 110 a and asecond half 110 b. The first half 110 a mounts to the first mountingsurface 60 a, while the second half 110 b mounts to the second mountingsurface 60 b. Each of the first half 110 a and second half 110 b has aledge or flange 110 c that engages the third mounting surface 60 c. Inoverall configuration, it will be seen that each of the first half 110 aand second half 110 b is “L”-shaped in cross-section. In addition, eachof the first half 110 a and second half 110 b has a top edge 110 d thatengages the fourth mounting surface 60 d. The first half 110 a andsecond half 110 b each have a rear surface 110 e that engages the uppersecondary shear blade 34 at forward edge 34 a. The first half 110 a andsecond half 110 b each have a bottom edge 110 f.

As best seen in FIG. 6, the replaceable shearing tip 110 is preferablymounted to the tip mounting portion 60 by socket head or spline-headcap-screws 120. Holes 122 are drilled through the first half 110 a andthe second half 110 b to receive the cap-screws 120. The second half 110b is preferably tapped with internal threads that engage externalthreads on the cap-screw 120. The first half 110 a is preferablycounter-bored with counter-bores 124 to receive the head 120 a of thecap-screw 120. As can be seen, most preferably the thickness of thefirst half 110 a that has the counter-bore 124 is equal to or greaterthan the thickness of the second half 110 b. Also, the thickness of thenarrowed upper jaw tip portion 70 is equal to or greater than thicknessof either the first half 110 a or the second half 110 b. Further, asseen best in FIG. 8, the thickness of d1 the material of the first half110 a beneath and supporting the cap-screw head 120 a is less than thedepth d2 of the cap-screw head counter-bore 124. These structuralfeatures provide structural strength to the components.

For stress relief, it is highly preferred that the top edge 110 d isradiused where it meets the third mounting surface 60 c, which issimilarly radiused. Also, the bottom ledge or flange 110 c is partiallyradiused where it meets the third mounting surface 60 c. See FIG. 6.

As a result of the above structure, as seen in FIGS. 7 a and 7 b, thereplaceable shearing tip 110 will seat against the upper movable jaw 14on at least three separate surfaces or seats: surfaces 60 c, 60 d, and34 a. This is in addition to the mounting surfaces 60 a and 60 b on thenarrowed upper jaw tip portion 70. This feature greatly relieves stresson the tip 110 and serves to hold the tip 110 firmly in place on theupper jaw 14 as the tip 110 pierces and is later withdrawn from theworkpiece.

In addition, the structure of the replaceable shearing tip 110encapsulates the narrowed upper jaw tip portion 70 and protects it. Thetip 110 is more durable than previous replaceable tips and the fasteningsystems used therewith. Because the tip 110 is constructed of pairedhalves 110 a, 110 b, in the event that one of the halves is damaged, itis only necessary to replace that half and not the whole tip.

The socket-headed or spline-headed cap-screws 120 allow the tip 110 tobe attached to the upper jaw 14 without bolts, improving strength andallowing more material to be used in the upper jaw. Further, an Allenwrench can be used to drive the socket-headed cap-screws 120 into thebores 124, instead of using a box-end wrench of socket wrench on theoutside of the screw heads 120 a. This requires less material to beremoved from the upper jaw 14.

Applicant has found that, for optimum performance and reliability of thereplaceable shearing tip 110, a number of important angularrelationships between the parts thereof and the upper jaw 14 are highlydesirable.

First, as best seen in FIGS. 5 and 10, an angle α1 between the bottomedge 110 f of each of the first half 110 a and second half 110 b and thelower edge 34 b of the secondary shear blade 34 should be in the rangeof −10° to +35. FIG. 10 shows an angle α1 of +10°. This optimizationtends to prevent the piercing tip 110 from moving outward from thesecondary blade 34 as the piercing tip 110 contacts the workpiece.

Second, as best seen in FIGS. 5 and 9, an angle α2 between the fourthmounting surface 110 d and the top edge 34 c of the secondary shearblade 34 should be in the range of −20° to +25°. FIG. 9 shows an angleα2 of +10°. This optimization helps to hold the tip 110 in place on theupper jaw 14 from a force trying to push the tip 110 forward from theforward edge 34 a of the secondary shear blade 34.

Third, as best seen in FIGS. 5 and 11, an angle α3 between the frontsurface 110 g of either the first half 110 a or the second half 110 b,and the lower edge 34 b of the secondary shear blade 34 should be in therange of 55° to 75°. In the embodiment shown in the phantom line L inFIG. 12, the angle α3 is measured between the lower edge 34 b and a lineL from the top corner 110 g 1 to the bottom corner 110 g 2 of the frontsurface 110 g.

Fourth, as best seen in FIG. 12, an angle α4 between the bottom edge 110f of the replaceable shearing tip 110 and the ledge or flange 110 cshould be in the range of −15° to +15°.

FIG. 14 shows the sequence of positions that the tip 110 will takewithin the lower jaw 12 as the upper jaw 14 closes on the lower jaw 12.It will be seen that force directed against the tip 110 by the workpiecewill result in force being applied to the secondary shearing blade 34 ata variety of angles as the tip successively encounters and thepenetrates the workpiece (not shown). The structure of the tip 110serves to keep the tip 110 firmly in contact with the secondary shearblade 34 with minimum stress.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof, and it istherefore desired that the present embodiment be considered in allrespects as illustrative and not restrictive reference being made to theappended claims rather than to the foregoing description to indicate thescope of the invention.

1. A heavy-duty demolition shear with a replaceable shearing tip, theapparatus having a lower jaw and an upper jaw pivotally connected to thelower jaw, the upper jaw having a primary shearing blade and a secondaryshearing blade, comprising: (a) a tip mounting portion on the upper jaw;and (b) a replaceable shearing tip mountable to the tip mountingportion, wherein the replaceable shearing tip further comprises twosections encompassing the tip mounting portion there-between.
 2. Theapparatus of claim 1, wherein the two sections are substantiallyL-shaped.
 3. The apparatus of claim 1, wherein the tip mounting portionis narrower than the remainder of the upper jaw.
 4. The apparatus ofclaim 1, wherein the two sections are connected to the tip mountingportion by fasteners which lie entirely within the two sections.
 5. Theapparatus of claim 4, wherein the fasteners are screws with a sockethead accepting an Allen wrench-type tool.
 6. The apparatus of claim 5,wherein one of the sections is counter-bored to accept the socket headand the other section is tapped to accept the other end of the screw. 7.The apparatus of claim 1, wherein the upper jaw further comprises atleast three seats for engaging the replaceable shearing tip.
 8. Theapparatus of claim 7, wherein one of the at least three seats is aforward edge of the secondary shear blade, and wherein the replaceableshearing tip abuts firmly against the forward edge without a gap.
 9. Theapparatus of claim 7, wherein the two sections of the replaceableshearing tip are L-shaped, and wherein one of the at least three seatsengages the long arm of the L.
 10. The apparatus of claim 9, wherein theseat engaging the long-arm of the L is radiused.
 11. The apparatus ofclaim 9, wherein one of the at least three seats engages the short armof the L.
 12. The apparatus of claim 11, wherein the seat engaging theshort arm of the L is radiused.
 13. The apparatus of claim 1, whereineach section has a bottom edge and the secondary shear blade has a loweredge, and wherein an angle between the section bottom edge and thesecondary shear blade lower edge is in the range of −10° to +35°. 14.The apparatus of claim 9, wherein the secondary shear blade has a topedge, and wherein an angle between the seat engaging the long arm of theL and the top edge of the secondary shear blade is in the range of −20°to +25°.
 15. The apparatus of claim 1, wherein each section has a frontsurface and the secondary shear blade has a lower edge, and wherein anangle between the front surface and the secondary shear blade lower edgeis in the range of 55° to 75°.
 16. The apparatus of claim 11, whereineach section has a bottom edge and the short arm of the L has a ledgeengaging the seat, and wherein an angle between the bottom edge and theledge is in the range of −15° to +15°.
 17. The apparatus of claim 6,wherein the section that is counter-bored has a thickness equal to orgreater than the thickness of the section that is tapped.
 18. Theapparatus of claim 1, wherein the thickness of the tip mounting portionis equal to or greater than the thicknesses of the sections.
 19. Theapparatus of claim 17, wherein the thickness of the section that iscounter-bored under the counter-bore supporting the screw head is lessthan the depth of the counter-bore.
 20. A heavy-duty demolition shearwith a replaceable shearing tip, the apparatus having a lower jaw and anupper jaw pivotally connected to the lower jaw, the upper jaw having aprimary shearing blade and a secondary shearing blade, comprising: (a) atip mounting portion on the upper jaw; and (b) a replaceable shearingtip mountable to the tip mounting portion, wherein the replaceableshearing tip further comprises two sections encompassing the tipmounting portion there-between, wherein the two sections aresubstantially L-shaped, (c) wherein the upper jaw further comprises atleast three seats for engaging the replaceable shearing tip, one of thethree seats engaging the long arm of the L-shaped section; and (d)wherein the secondary shearing blade has a top edge, and an anglebetween a seat engaging the long arm of the L-shaped section and the topedge of the shearing blade is in the range of −20° to +25°.
 21. Aheavy-duty demolition shear with a replaceable shearing tip, theapparatus having a lower jaw and an upper jaw pivotally connected to thelower jaw, the upper jaw having a primary shearing blade and a secondaryshearing blade, comprising: (a) a tip mounting portion on the upper jaw;and (b) a replaceable shearing tip mountable to the tip mountingportion, wherein the replaceable shearing tip further comprises twosections encompassing the tip mounting portion there-between, eachsection having a bottom edge, and (c) wherein the secondary shearingblade has a lower edge, and wherein an angle between the section bottomedge and secondary shearing blade lower edge is in the range of −10° to+35°.
 22. A heavy-duty demolition shear with a replaceable shearing tip,the apparatus having a lower jaw and an upper jaw pivotally connected tothe lower jaw, the upper jaw having a primary shearing blade and asecondary shearing blade, comprising: (a) a tip mounting portion on theupper jaw; and (b) a replaceable shearing tip mountable to the tipmounting portion, wherein the replaceable shearing tip further comprisestwo sections encompassing the tip mounting portion there-between,wherein the two sections are substantially L-shaped, each section havinga front surface and (c) wherein the secondary shearing blade has a loweredge, and an angle between the front surface and the secondary shearingblade lower edge is in the range of 55° to 75°.
 23. A heavy-dutydemolition shear with a replaceable shearing tip, the apparatus having alower jaw and an upper jaw pivotally connected to the lower jaw, theupper jaw having a primary shearing blade and a secondary shearingblade, comprising: (a) a tip mounting portion on the upper jaw; and (b)a replaceable shearing tip mountable to the tip mounting portion,wherein the replaceable shearing tip further comprises two sectionsencompassing the tip mounting portion there-between, wherein the twosections are L-shaped, each having a bottom edge and the short arm ofthe L-shaped section has a ledge thereon for mounting to the tipmounting portion, and (c) wherein an angle between the bottom edge andthe ledge is in the range of −15° to +15°.